This invention relates to a parking lock mechanism for a shift lever in an automobile equipped with a clutch of the type which is held in released state when the engine is stopped, such as a fluid operated clutch or electromagnetic clutch or others.
In an automobile having a transmission equipped with a torque converter or an electromagnetic clutch, when the engine stops, the clutch is disengaged, so that the engine is disconnected from the power transmission system. Therefore, when parking the automobile with its engine stopped, the braking effect of the engine cannot be used for parking the automobile even if one of the gears of the transmission is kept in engagement with another gear. Therefore, in an automobile of this kind, a parking position for a shift lever is provided in a shift pattern and a lock mechanism is provided to lock one of rotary shafts in the power transmission system.
For example, since a four speed transmission has a vacant position in the shift pattern at an opposite side to the reverse gear position, the parking position is set at the vacant position. When the shift lever is shifted to the parking position, a shifter rail connected to the reverse gear is shifted in the direction opposite to that of the reverse shifting which causes a pawl to engage with a parking gear secured to the rotary shaft. In such a system, if the shift lever slips from the parking position, the parking lock is released which can cause an unforeseen accident. In order to avoid such a danger, a method of locking the parking lock system in the parking position by using the force of a click spring for causing an accentuation in the shift lever operation has been proposed.
Japanese Patent Laid Open No. 55-166723 discloses a lock mechanism for the shift lever. The lock mechanism is provided with a select lever, an engaging portion of which is selectively engaged with one of the shifter arms by operating a shift lever and the engaging portion is engaged with a pawl of an adjacent shifter arm for locking the shift lever. The engaging portion of the select lever is in U-shaped form for the engagement, which will reduce the strength of the engaging portion.